FDA Approves New ALS Drug Despite Uncertain Data

FRIDAY, Sept. 30, 2022 (HealthDay News) -- The U.S. Food and Drug Administration on Thursday gave its approval to a new drug for amyotrophic lateral sclerosis (ALS). But approval of the drug, called Relyvrio (sodium phenylbutyrate/taurursodiol), is bound to stir new questions, with some doubting the strength of data supporting its effectiveness. Patient advocate groups had strongly lobbied the FDA for its approval, however.

The drug's path to approval has been a rocky one. Last March, an FDA panel looking at the drug voted 6-4 against approval. But following a rare second review, the same panel on Sept. 8 voted 7-2 to support approval for the experimental drug.

In the statement issued by the agency on Thursday, the FDA pointed to data from a six-month randomized clinical trial. "In the trial, 137 adult patients with ALS were randomized to receive either Relyvrio or placebo. The patients treated with Relyvrio experienced a slower rate of decline on a clinical assessment of daily functioning compared to those receiving a placebo," the agency said. Longer-term tracking of patients who had taken Relyvrio also suggested improved survival.

The medication combines a dietary supplement used in traditional Chinese medicine with an existing prescription drug for liver disorders. The combination shields cells from premature death, the manufacturer of Relyvrio, Amylyx Pharma, contends.

Relyvrio can have side effects, the FDA noted. "The most common adverse reactions experienced with Relyvrio were diarrhea, abdominal pain, nausea and upper respiratory tract infection," the agency said. "Relyvrio contains taurursodiol, a bile acid, which may cause worsening diarrhea in patients with disorders that interfere with bile acid circulation."

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